Results of safety study of radiopharmaceutical drug preparation based on albumin microspheres of 5-10 μm diameter labeled with rhenium-188

Inflammatory joint diseases, such as rheumatoid, psoriatic, reactive arthritis, ankylosing spondylitis, reactive and other arthritis, lead to significant loss of quality of life and are frequent causes of disability. These diseases are accompanied by synovitis, which continues to progress despite the ongoing basic therapy. Radiosynovectomy (RSE) is one of the effective methods of treatment of such patients. A radiopharmaceutical drug based on human blood albumin microspheres with a diameter of 5-10 μm labeled with rhenium-188 for the treatment of knee arthrosis (Arthroren-MRRC) was developed at the A. Tsyb MRRC. The results of phase 1 clinical trials are presented, the aim of which is to study the tolerability, safety and pharmacokinetics of the drug during knee joint RSE (single intra-articular injection for the treatment of chronic recurrent synovitis); to study the increasing activities (370, 555, 740 and 925 MBq), to evaluate the radiation doses, the effect of RSE with the use of radiopharma-ceutical on the quality of life of patients, radiation exposure to personnel. 20 patients (18-75 years old) with recurrent chronic synovitis of the knee joint underwent RSE with injection of 188Re MCA 5-10 μm with activity ranging from 370 to 925 MBq. After injection, the following was performed: time-lapse SPECT/CT scintigraphy (1-72), radiometry of urine taken within 48 h after RSE and estimation of absorbed internal radiation doses to the synovial membrane and organs at risk. The absorbed doses formed after RSE in the knee joint in patients ranged from 17.5 to 74 Gy, and the doses to the organs at risk were many times lower than the generally accepted dose limits. High safety and good tolerability of radiopharmaceutical (188Re MCA 5-10 μm) was demonstrated. The activity of 740 MBq appeared to be optimal in terms of safety and efficacy in knee joint RSE.